1. Field of the Invention
The present invention relates to an image former of inkjet type, and particularly to an image former allowing for a printing with a suppressed mist production in a low temperature range.
2. Description of Related Arts
There has been spread use of inkjet type printers including print heads configured with arrays of nozzles through which ink droplets are propelled onto a print sheet to form an image. In inkjet printers, print heads have had their ink propelling mechanisms configured with arrays of piezoelectric devices or such for propelling ink droplets in accordance with applied drive voltages.
In the patent literature 1 (Japanese Patent Application Laid-Open Publication No. H6-218928), there has been description of an ink jet head including nozzles with menisci formed therein in vicinities of the openings by surface tension of ink, causing ink droplets to be propelled with different sizes or flying speeds depending on positions of menisci relative to nozzle openings.
For use in inkjet printers, there have been various kinds of ink available with a typical property tending to have increased viscosities under low-temperature environments, constituting a difficulty to secure an adequate discharge rate with normal drive voltages. To this point, there has been a warm-up of ink at low temperatures, with a pause of print until an arrival at an adequate temperature of ink. Accordingly, a start of printing has been delayed under low-temperature environments, as an issue.
In the patent literature 2 (Japanese Patent Application Laid-Open Publication No. 2007-296754), there has been description of mist (sometimes referred to as satellites) being unnecessary minute ink droplets produced along with ink discharge, adhering to, among others, the printer housing and print sheets, degrading the print quality, as another issue.